1. Field of the Invention
The present invention relates to a motorcycle frame that is reinforced so as to be sufficiently rigid for use in extreme conditions, while being light in weight.
2. Description of the Background Art
In general, it is known to provide a motorcycle having frame components which include main frames and a down tube, where the main frames extend from a head pipe in a rearward direction of a body, and the down tube extends under this main frame and extends from the head pipe in a downward direction of the body.
For motorcycles having such frame components, it has been proposed that frame components, including a head pipe, a main frame, a down tube and the like, are integrally cast using light metal materials such as magnesium alloy in order to minimize vehicle body weight. Such a motorcycle is disclosed, for example, in Japanese Laid-open Patent Application No. Sho 60-176876.
In a motorcycle trial race, since there may be an event where a motorcycle drops, for example, through a distance of 10 meters in height, the motorcycle used for a motorcycle trial race is required to have enough strength to sustain impacts caused by such falls.
However, when a motorcycle is designed according to the convention of minimizing the weight of the motorcycle body, and when such a motorcycle is used for trial racing, it is necessary to stiffen respective frame components in the body portion to which a load is applied.
The present invention was made in consideration of the above described problem, and an object thereof is to provide a motorcycle frame, the rigidity of which is secured while maintaining a light frame weight.